This cartoon is another variation on a standard theme from the era. The family pet is on its last chance. Any more noise, messes, trouble, etc., and out it goes. Then a cute little animal, or trio of animals in this case, show up to cause havoc. The family pet struggles to protect the newcomer, while taking the blame for its damage. Warner Bros did it. MGM did it. Here, from the Internet Archive, is Famous Studios' version: Hector's Hectic Life.